Two-wheeled self-balancing motorized personal vehicle with tilting wheels

ABSTRACT

A vehicle with two independently rotatable wheels arranged opposite from each other and bridged by a linking structure, having a driving motor for each wheel, and having electronic fore-and-aft self-balancing capabilities. The two wheels are capable of tilting side-to-side in unison to execute turns. The vehicle is operated by the rider leaning forward, backward, or sideways to direct travel in the direction of leaning. Further means are provided for producing advantages in stability and portability.

FIELD OF THE INVENTION

The present invention relates to vehicles having two wheels arrangedopposite from each other between which a human rider can stand; and inparticular, to those wherein the two wheels do not share a common axle.It also relates to motorized vehicles having fore-and-aft self-balancingcapabilities.

BACKGROUND OF THE INVENTION

The most well-known example of a self-balancing motorized vehicle withtwo wheels arranged opposite from each other, wherein a person can ridethe vehicle by standing on a foot support(s) between the wheels, isdisclosed as the main embodiment of U.S. Pat. No. 6,302,230 [Sramek etal?]. (That embodiment is commercially known as the “Segway”.) Thevehicle of the '230 patent has a handlebar means which serves to assistthe standing rider's stability, and to carry an interface for steeringthe vehicle. This vehicle is an effective short- or medium-distancetransportation method; however, some users' needs would be better met bya vehicle having similar configuration of wheels and similarfore-and-aft balance means, but without a handlebar. In particular, sucha vehicle would provide greater portability and greater convenience inmounting and dismounting, as well as the opportunity to have both handsfree, all of which are advantageous in many circumstances.

However, if a rider of a vehicle with this type of wheel configurationhas no points of contact with any part of the vehicle other than thesurface(s) which support his feet—this includes the absence of ahandlebar—then he may have difficulty keeping his ankles and kneesstable. Although the vehicle itself is capable of remaining balanced inthe fore-and-aft plane, the riding stance may be too unsupported and“loose” for the average person to maintain comfortably, as he mustregulate the positions of his feet and legs in relation to the vehiclein addition to directing the vehicle's travel. Such a vehicle thusrequires new means for supporting rider stability. It also requires newmeans by which the rider can control the vehicle's steering.Additionally, new and better means for improving portability, stability,and/or intuitiveness of control are demands which always exist in thisand related fields.

SUMMARY OF THE INVENTION

The present invention is a vehicle with two independently rotatablewheels arranged opposite from each other, having a driving motor foreach wheel and also having self-balancing capabilities in thefore-and-aft plane. The vehicle is capable of supporting a human riderbetween the two wheels; the rider controls the movement of the vehicleby shifting her weight in the fore-and-aft plane and by leaning to theleft and to the right. The frames are connecting by a linking structureconfigured such that the wheels are capable of tilting side-to-side inunison during turns. This may be achieved by means of a plurality ofparallel linking members each pivotably coupled to both frames, whereinat least two of the linking members are disposed at different heightsrelative to the riding surface. The tilting capability of the wheelsprovides improved stability and comfort during turns.

The vehicle may be capable of converting to a folded position in whichthe wheels are closer together for carrying or stowage, by means such ashinges in the linking members. The vehicle in folded position may becarried by means of a handle coupled to the linking structure, and thehandle may extend clear of the wheels and the frames when the vehicle isfully folded.

The vehicle is configured such that the rider may stand on foot supportsurfaces between the two wheels with one leg in firm contact with theinward-facing side of each frame. This increases the amount anddistribution of points of contact between the rider's body and thevehicle, which dramatically improves the stability and ease of use ofthe vehicle in the absence of a handlebar. To aid the rider in usingfrictional contact with the frames to stabilize her legs, special legcontact surfaces may be provided on the frames. These leg contactsurfaces may be made from a material which provides greater frictionthan that of the frames; they be also slightly curved to fit the generalshape of the rider's legs.

DRAWINGS Brief Description of Figures

FIG. 1 shows a perspective view of one embodiment of a personal vehiclein accordance with the present invention.

FIG. 2 shows a perspective view of the vehicle of FIG. 1 with wheelstilted to one side, as during a turn.

FIG. 3 shows a top perspective view of the vehicle of FIG. 1 with itslinking structure partially folded.

FIG. 4 shows a side view of the vehicle of FIG. 1 with its linkingstructure fully folded and handle extended.

FIG. 5 shows a perspective view of a different embodiment of a personalvehicle in accordance with the present invention, which wheels tilted toone side as during a turn.

FIG. 6 shows a detail of a perspective view of another embodiment of apersonal vehicle, having a bias means and locking mechanism inaccordance with the present invention.

DRAWINGS-List of Reference Numerals 100 Vehicle (FIG. 1) 110 First wheel111 Second wheel 120 First frame 121 Second frame 130 Linking structure131 Linking member(s) 132 Hinge(s) 133 Handle 140 Foot supportsurface(s) 150 Leg contact surface(s) 200 Vehicle (FIG. 5) 210 Firstwheel 211 Second wheel 220 First frame 221 Second frame 230 Linkingstructure 231 Linking member(s) 240 Foot support surface(s) 250 Legcontact surface(s) 300 Vehicle (FIG. 6) 311 Second wheel 321 Secondframe 330 Linking structure 331 Linking member(s) 333 Handle 340 Footsupport surface(s) 350 Locking mechanism 351 Sliding element 352 Lockingpiece 353 Locking pin 354 Bias means

DETAILED DESCRIPTION

Referring to FIG. 1, a perspective view of a personal vehicle inaccordance with the present invention is shown. Vehicle 100 comprisestwo wheels 110 and 111, each respectively connected to a frame 120 and121; a linking structure 130 coupled at one end to frame 120 and at theother end to frame 121, for connecting the two frames; two foot supportsurfaces 140 positioned between wheels 110 and 111 for a person to standon; and a handle for carrying vehicle 110, coupled to linking structure130. Wheels 110 and 111 are arranged opposite from each other, but donot share a common axle, and are therefore independently rotatable andcapable of spinning at different speeds and/or in opposite directions.The wheels may be of a wide range of sizes, but those shown in FIG. 1are relatively large, having a diameter comparable to the length of anadult person's lower leg. Each of wheels 110 and 111 is respectivelycoupled to some kind of frame structure 120 and 121, which can beimplemented in various possible forms as long as they connect wheels 110and 111 to linking structure 130. In this embodiment, frames 120 and 121are formed as shells or housings in which wheels 110 and 111 are encasedand partially enclosed. In addition to their primary function ofconnecting wheels 110 and 111 to linking structure 130, frame structures120 and 121 may also serve other purposes such as supporting and guidingwheels 110 and 111, protecting wheels 110 and 111 from rain, dirt, etc.,or shielding wheels 110 and 111 from coming into contact with therider's body or clothes.

Linking structure 130 is disposed generally horizontally, and is coupledat one end to frame 120 and at the other end to frame 121. It comprisesthree linking members 131—two on the same horizontal plane, and a thirdpositioned below the first two. (Other numbers and configurations oflinking members 131 are possible, provided that at least two of them areat different heights relative to the riding surface.) Linking members131 are parallel to each other, and each is pivotably coupled to both offrames 120 and 121 such that wheels 110 and 111 can tilt from side toside relative to linking structure 130 without significantly disruptingthe horizontal disposition of linking structure 130. The arrangement ofat least two of linking members 131 at different heights serves to linkwheels 110 and 111 to each other such that any tilting of the wheelsmust occur simultaneously, in the same direction, and to generallysimilar degrees. (If the wheels are parallel to each other theirrespective magnitudes of change in angle will always be substantiallyequal. If the wheels are cambered, their respective magnitudes of changein angle may not be substantially equal but will be generally similar.)These features of linking structure 130 are important to achieving thecapability of wheels 110 and 111 to tilt or lean in the direction of aturn, which provides greater stability during turns and reduces thechances of tipping.

FIG. 2 shows vehicle 100 during a left turn. In order to initiate a leftturn, the rider leans sideways to the left, which pushes wheels 110 and111 to tilt in unison to the left. (This tilting action activates atilt-detecting means in the electronic control system, described infurther detail below.) The tilting of each wheel occurs on an axisgenerally aligned with the direction of travel (i.e., the change inangle each wheel incurs during tilting is generally in a vertical planeoriented perpendicular to the direction of travel). Linking members 131,being pivotably coupled to both of frames 120 and 121, are notsubstantially angularly displaced away from horizontal; but those oflinking members 131 which are positioned at different heights shifthorizontally relative to each other. (It is shown in FIG. 2 that the twoupper linking members have shifted left relative to the lower linkingmember.) This allows linking structure 130 to remain generallyhorizontal while wheels 110 and 111 lean into the turn. Foot supports140, being rigidly coupled to the two top linking members 131, likewiseremain generally horizontal. These features increase safety and comfortfor the rider. Additionally, the shifting action of linking members 131result in slight shifts in horizontal and vertical position of footsupports 140, which may make it smoother and more comfortable for therider to shift his weight sideways.

Note that the foot support surfaces shown in these figures are specificembodiments of a general load-bearing surface or surfaces which maysupport a person, and which may also be used to carry various objectseven without a human rider. These load-bearing surfaces can be ofvarious shapes and sizes and may be coupled to the linking structure orto the frame(s).

FIG. 3 shows vehicle 300 in a partially folded state. For convenience ofcarrying and stowage, means is provided for vehicle 300 to convert intoa collapsed position in which wheels 110 and 111 are closer togetherthan they are when the vehicle is in use. In this example, this functionis achieved by folding of linking structure 130. In particular, each ofthe three linking members 131 has a hinge 132. In this embodiment eachof hinges 132 is located in the middle of its respective linking member,but in general hinges 132 need only be arranged such that their combinedfolding constitutes folding of the entire linking structure 130.

A handle 133 may be coupled to one or more of linking members 131. Inthe embodiments shown, handle 133 is positioned in the middle of linkingstructure 130, in substantially the same vertical plane as hinges 132.When handle 133 is pulled upward, the force transmitted to hinges 132(in conjunction with the weight of wheels 110 and 111) causes linkingstructure 130 to fold, as shown in FIG. 3, bringing wheels 110 and 111closer together. Handle 133 can then be used to carry the folded unit byhand.

Handle 133 may furthermore be extendable, as in FIG. 4 wherein linkingstructure 130 is completely folded. This feature of handle 133 isembodied here as a sliding element 151 coupled to handle 133 rigidly,and coupled to linking members 131 so as to be vertically movablethrough a certain range. Sliding element 151 therefore allows handle 133to move vertically relative to its point(s) of attachment to linkingstructure 130. When handle 133 is pulled upward it first slides to itsfully extended position; further upward force causes linking structure130 to fold as described above. Handle 133 and sliding element 151 isconfigured such that when linking structure 130 is fully folded, handle133 extends beyond the topmost edges of wheels 110 and 111 and/or frames120 and 121, thereby allowing a person to carry vehicle 100 with herhand clear of the wheels and the frames. This provides for greatercomfort for the person carrying the vehicle, and also allows the wheelsto be very close together in folded position.

Note that there exist other possible means, other than the specificsliding mechanism described here, by which the handle may be made toextend beyond the wheels and the frames.

In order to achieve optimum stability, the rider preferably stands withhis lower legs firmly in contact with frames 120 and 121. This createsmultiple points of contact between the rider and the vehicle so that therider can easily hold his feet and lower legs in position. To aid inthis, vehicle 100 further comprises two leg contact surfaces 150, onecoupled to each of frames 120 and 121. Leg contact surfaces 150 areaffixed to the inward-facing sides of frames 120 and 121, and positionedsuch that they can come into contact with the lower legs of a riderstanding with one foot on each of foot support surfaces 140. Leg contactsurfaces 150 may be made from a soft, yielding, and/or texturedmaterial, in order to provide friction which aids the rider instabilizing his legs against frames 120 and 121. They may furthermore beslightly curved concavely around a substantially vertical axis to fitthe general shape of the rider's legs.

FIG. 5 shows a perspective view of a different embodiment of the vehicleof the present invention, with a configuration of foot support surfacesalternative to those of the previous embodiments. Vehicle 200 compriseswheels 210 and 211, frames 220 and 221, linking structure 230 withlinking members 231, and leg contact surfaces 250, which performessentially the same functions as their counterparts in vehicle 100.(This embodiment does not include means for folding linking structure230, or a handle.) However, vehicle 200 further comprises two footsupport surfaces 240, one of which is rigidly coupled to theinward-facing side of each of frames 220 and 221. These foot supportsurfaces 240 may be individual pieces which are rigidly coupled toframes 220 and 221, or they may simply be each molded from the samepiece of material as their respective frames 220 and 221.

FIG. 6 shows a detail of a perspective view of a vehicle 300. Inaddition to the same features of vehicle 100, vehicle 300 furthercomprises a bias piece 354, and a locking mechanism 350 associated withhandle 333. Handle 333 is rigidly coupled to sliding element 351, whichis capable of sliding substantially vertically relative to linkingstructure 330; thus handle 333 is extendable in the same manner aspreviously described for vehicle 100. Bias piece 354 is made of anelastic material such as rubber, and is firmly attached to either handle333 or linking structure 330 such that it can be pinned between somepart of handle 333 and some part of one of linking members 331. In theembodiment shown, bias piece 354 is formed as a rectangular block firmlyattached beneath one end of handle 333. Vehicle 330 can be convertedfrom a folded position (see FIGS. 3 and 4) into an unfolded position bypushing downward on handle 333 while vehicle 300 is set generallyupright on a surface. Starting from its fully extended position, handle333 first slides downward along sliding element 351, and then furtherdownward force causes linking structure 330 to unfold until linkingmembers 331 are substantially straight and bias piece 354 is in contactwith both handle 333 and one of linking members 331. Locking mechanism350 engages to hold the structure in this position.

The locking mechanism 350 of this embodiment has a locking piece 352rigidly coupled to sliding element 351. Locking piece 352 engages withlocking pin 353 on the lower linking member, and prevents linkingstructure 330 from folding when not desired (due to the elasticity ofbias piece 354 or any other cause). When the wheels lean during a turn,linking members 331 shift horizontally relative to each other aspreviously described. Handle 333 remains in the same position relativeto the upper two linking members, and locking piece 352 remains engagedwith locking pin 353 on the lower linking member. The resultant tensioncreated in sliding element 351 deforms and/or compresses bias piece 354,which due to its elasticity tends to return to its original shape,thereby biasing the entire structure to a neutral, non-turning position(i.e., a position in which the wheels are not substantially tilted tothe left or to the right and are substantially mirror images of eachother).

Each wheel is driven by a respective motor. In the embodiments shown,the motors are housed within their respective frames and are notexposed. The motors are directed by an electronic control means whichenacts automatic fore-and-aft balancing of the vehicle. (A singleelectronic control means may control both motors, or each wheel may haveits own independent electronic control means which control theirrespective motors.) The electronic control means is capable of sensingforward or backward tilting of the vehicle—by gyrosensors,accelerometer, or other means known in the art—and responds by directingthe motors to accelerate or decelerate appropriately in order tomaintain equilibrium in a fore-and-aft balanced position. (The balancedposition is considered to be one in which the axis on which theside-to-side tilting of each wheel occurs is approximately horizontal.)The same mechanism enables the rider, standing on foot support surfacesbetween the two wheels, to direct the vehicle's forward and backwardtravel through shifting of her center of gravity. She can shift herweight forward or backward to cause the vehicle to accelerate in thatdirection, and can shift her weight in the direction opposite that inwhich the vehicle is moving to cause the vehicle to decelerate.

As described above, the rider initiates a turn by leaning sidewaystoward the desired direction of the turn, whereupon the wheels tiltsideways, remaining in contact with the rider's legs, and the linkingmembers shift horizontally relative to each other. The electroniccontrol means may comprise a means for detecting one or more of thesechanges. For example, the electronic control means may sense thesideways tilting of one or more of the wheels (via gyroscope,accelerometer, etc.). It then adjusts the respective speeds and/ordirections of one or both of the wheels, thereby creating a differencein velocity which causes the vehicle to turn toward the direction inwhich the rider has shifted her weight. The combination of thesesteering controls and the fore-and-aft controls create a simple andintuitive means for a rider to operate the vehicle.

The motors may drive the wheels through a type of drive mechanism knownin the art and sometimes called a “friction drive”. For instance, eachof the two motors may drive a spinning cylindrical component which mayhave a small radius compared to that of the wheel, and which is incontact with the inner rim of the wheel. Friction between the surface ofthe spinning component and the inner rim of the wheel provides the gripnecessary for the motor to transmit torque to the wheel. The frictiondrive mechanisms may be used in conjunction with hubless wheels, whichare substantially lighter-weight than wheels having center hubs andwhich therefore enhance the portability of the vehicle.

1. A personal vehicle comprising: a first wheel and a second wheel,independently rotatable, positioned opposite from each other, andseparated by a distance; a first motor for driving said first wheel anda second motor for driving said second wheel; a first frame attached tosaid first wheel and a second frame attached to said second wheel; alinking structure coupled to both said first frame and said secondframe; and at least one electronic control means for controlling saidfirst and second motors; wherein each of said first and second wheelsare capable of tilting side-to-side in unison about a respective wheeltilting axis, relative to the riding surface; and wherein said at leastone electronic control means enacts fore-and-aft balancing of saidvehicle such that each of said wheel tilting axes is maintained in agenerally horizontal orientation.
 2. The vehicle of claim 1, whereinsaid vehicle is capable of converting between an unfolded position and afolded position, in which said distance between said first and secondwheels is lesser in said folded position than in said unfolded position.3. The vehicle of claim 1, wherein said linking structure comprises atleast two independent elongated linking members, each coupled to both ofsaid first and second frames, wherein at least two of said at least twolinking members are positioned at different heights.
 4. The vehicle ofclaim 2, further comprising a handle coupled to said linking structureby means of which said vehicle may be carried when said vehicle is insaid folded position.
 5. The vehicle of claim 4, wherein said handle iscapable of extending beyond the uppermost edges of said first and secondframes when said vehicle is in said folded position.
 6. The vehicle ofclaim 1, wherein said first and second wheels have a negative camberangle.
 7. The vehicle of claim 6, wherein said vehicle is capable ofconverting between an unfolded position and a folded position, saiddistance between said first and second wheels being lesser in saidfolded position than in said unfolded position; and wherein said firstand second wheels are substantially parallel to each other when saidvehicle is in said folded position.
 8. The vehicle of claim 1, furthercomprising at least one leg contact surface on each of said first andsecond frames for contacting said person's legs, said leg contactsurfaces being fabricated from a yielding material and also beingslightly curved concavely around a generally vertical axis.
 9. Thevehicle of claim 1, further comprising a wheel tilt bias means forbiasing said first and second wheels to a position in which they aresubstantially mirror images of each other.
 10. The vehicle of claim 1,wherein each of said first and second motors transmits torquerespectively to said first and second wheels through frictional contactbetween some part of said motor and some part of said wheel.
 11. Thevehicle of claim 1, further comprising at least one load-bearing surfacebetween said first and second wheels for supporting a person, or anobject or objects.
 12. The vehicle of claim 11, wherein said at leastone load-bearing surface is coupled to said linking structure.
 13. Thevehicle of claim 11, wherein said at least one load-bearing surface isrigidly connected to at least one of said first and second frames.